Specifically, it will make a single pass through your drive, doing a
byte-by-byte copy, and noting any sectors that it cannot read.
It will then go back and try to ready those semi-unreadable areas
using multiple methods, and approaching from both spinward and
antispinward directions, trying to sneak up on any kind of
readability. It does this just for those problematic areas of the
drive.
In other words, you get a mostly-good raw image of the drive in a
single pass very quickly. It then tries the hard areas, but doesn't
waste time on the already-read areas. So if the disk dies in
mid-rescue, it got as much as it could and you're always left with a
viable, writable-to-another-drive raw disk image.
Royce
On Thu, Mar 10, 2016 at 2:45 PM, Royce Williams <royce@tycho.org> wrote:
> Specifically for the "drive that's on its last legs" case, ddrescue is
> fantastic for minimizing how much you make the drive read vs how much
> you can rescue from it. It's brilliant in its simplicity.
>
> Royce
>
> On Thu, Mar 10, 2016 at 2:41 PM, Pat Borjon <borjonx@gmail.com> wrote:
>> I've heard great things about ddrescue but haven't used it myself. I'm a
>> crunchy old man who prefers to use the same old tools that've always worked
>> (for better or worse). I did some research recently before using cat and it
>> sounds like the sizing arguments help dd to an extent, but there are other
>> mem handle, kernel, lock & pipe reasons that cat typically has better
>> performance. I didn't attempt to become an expert on those details because
>> of that whole FIFO grey matter limitation coupled against that 24 hour/day
>> constraint, but was pleased w/the cat results.
>>
>> Let me know if you have any questions or if there's anything I can do to
>> help. I love linux & the simplicity of the powerful tools.
>>
>> Pat
>>
>>
>>
>>
>>
>> On Wed, Mar 9, 2016 at 8:52 PM, Jeremy Austin <jhaustin@gmail.com> wrote:
>>>
>>> That's interesting, Pat. Is it superior to ddrescue, for when there are
>>> actual errors to deal with?
>>>
>>> I've relied on the block size arguments for dd, and the occasional
>>> translations. Equivalents in cat, or irrelevant?
>>>
>>> TIA
>>>
>>> On Wed, Mar 9, 2016 at 4:52 PM, Pat Borjon <borjonx@gmail.com> wrote:
>>>>
>>>> fwiw, I've been using dd to copy linux & ms discs for almost 20 years,
>>>> and just last month found out cat is faster & appears to be less prone to
>>>> disc errors.
>>>>
>>>> Pat
>>>>
>>>>
>>>> On Wed, Mar 9, 2016 at 3:29 PM, Christopher Howard
>>>> <christopher@alaskasi.com> wrote:
>>>>>
>>>>> Yeah, actually I did use GParted yesterday. It has "slide" functionality
>>>>> which can slide a partition down the drive. So I shrunk C:, slide the
>>>>> recovery partition down, and then just used dd to copy everything over to
>>>>> the new drive. I found out that you want to have iotop running as well
>>>>> because dd doesn't seem to provide any kind of progress or transfer meter.
>>>>>
>>>>> On 03/09/2016 03:00 PM, Josh wrote:
>>>>>
>>>>> GParted is great. You can shrink your C: partition, then copy both the
>>>>> C: partition and the recovery partition to the smaller drive and not have to
>>>>> worrky about windows freaking out.
>>>>>
>>>>> On Tue, Mar 8, 2016 at 10:27 AM, Jeremy Austin <jhaustin@gmail.com>
>>>>> wrote:
>>>>>>
>>>>>> I recommend gparted. If you change the number and/or order of
>>>>>> partitions, you may need to manually edit BOOT.INI
>>>>>>
>>>>>> IIRC
>>>>>>
>>>>>> On Tue, Mar 8, 2016 at 10:16 AM, Christopher Howard
>>>>>> <christopher@alaskasi.com> wrote:
>>>>>>>
>>>>>>> I've got to copy a hard drive with a Windows system on it onto a
>>>>>>> smaller (replacement) hard drive. My approach was to just shrink the C:
>>>>>>> partition down small enough so that everything would fit on the smaller
>>>>>>> drive, and then just do a block-level copy with dd. Seems simple enough. The
>>>>>>> only oddity is that, for whatever reason, Windows install puts the 1GB
>>>>>>> Recovery Partition /after/ C: partition, so that after shrinking C:
>>>>>>> partition, there is like 70 GB of unallocated space between them, and the
>>>>>>> Recovery Partition is stuck way at the far end of the drive, foiling my
>>>>>>> plans.
>>>>>>>
>>>>>>> Can I just delete that Recovery Partititon? Windows Disk Management
>>>>>>> tool won't allow me to do it, but I'm sure my tools will. Personally, I
>>>>>>> don't care about having a Recovery Partition because I just I use my
>>>>>>> custom-made LXDE/Debian usb stick to do recoveries.
>>>>>>>
>>>>>>> --
>>>>>>> Christopher Howard, Computer Assistant
>>>>>>> Alaska Satellite Internet
>>>>>>> 3239 La Ree Way, Fairbanks, AK 99709
>>>>>>> 907-451-0088 or 888-396-5623 (toll free)
>>>>>>> fax: 888-260-3584
>>>>>>> mailto:christopher@alaskasi.com
>>>>>>> http://www.alaskasatelliteinternet.com
>>>>>>> https://www.linkedin.com/in/christopher-howard-9429ab52
>>>>>>>
>>>>>>> ---------
>>>>>>> To unsubscribe, send email to <nuga-request@lib.uaa.alaska.edu>
>>>>>>> with 'unsubscribe' in the message body. To manage your subscription,
>>>>>>> follow the directions at https://www.lib.uaa.alaska.edu/cgi-bin/lists.cgi
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Jeremy Austin
>>>>>>
>>>>>> (907) 895-2311
>>>>>> (907) 803-5422
>>>>>> jhaustin@gmail.com
>>>>>>
>>>>>> Heritage NetWorks
>>>>>> Whitestone Power & Communications
>>>>>> Vertical Broadband, LLC
>>>>>>
>>>>>> Schedule a meeting: http://doodle.com/jermudgeon
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Christopher Howard, Computer Assistant
>>>>> Alaska Satellite Internet
>>>>> 3239 La Ree Way, Fairbanks, AK 99709
>>>>> 907-451-0088 or 888-396-5623 (toll free)
>>>>> fax: 888-260-3584
>>>>> mailto:christopher@alaskasi.com
>>>>> http://www.alaskasatelliteinternet.com
>>>>> https://www.linkedin.com/in/christopher-howard-9429ab52
>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> Jeremy Austin
>>>
>>> (907) 895-2311
>>> (907) 803-5422
>>> jhaustin@gmail.com
>>>
>>> Heritage NetWorks
>>> Whitestone Power & Communications
>>> Vertical Broadband, LLC
>>>
>>> Schedule a meeting: http://doodle.com/jermudgeon
>>
>>
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Received on Thu Mar 10 13:10:42 2016
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